This invention relates to a memory card such as an IC card for use in a game machine and, more particularly, to a shutter for covering electrode terminals of the card.
The type of memory card that is used is an IC card which contains TV game software or as a desk card for use in a microcomputer system has a structure such as that shown in FIG. 1. A memory card 1 (hereinafter simply referred to as "card") has a multiplicity of electrode terminals 3 disposed on the obverse surface of a package 2 at one end thereof. The package 2 accommodates a semiconductor module 2b in which thin semiconductor modules, electronic parts, a thin cell battery such as a mercury cell, and so forth are incorporated. A shutter 4 is formed from a thin metallic plate and adapted to cover the electrode terminals 3. The shutter 4 is supported in such a manner that it can open or close by sliding in the longitudinal direction of the card as indicated by the arrow A. The shutter 4 has a pair of downwardly bent projections 4a formed at its extreme ends.
FIGS. 2 and 3 show, in plan and in a side view, a state in which the shutter 4 is slightly open. A pair of spring accommodation grooves 2a are formed in a front end portion of the obverse surface of the package 2 at opposite ends thereof. A spring-hitching pin 5 made of metal is fixed to a front end portion of each spring accommodation groove 2a, and spring-hitching pins 6 made of metal are fixed to the shutter 4. A return spring 7 which is formed of electrically conductive material is stretched between the pins 5 and 6 and functions to close the shutter 4 in a normal state. A pair of shutter receiving pins 9 are provided in a connector disposed on the side of a card reader (both not shown) and which correspond to the projections 4a of the shutter 4 of the card 1 inserted into the card reader.
If the card 1 is inserted into the connector, the projections 4a of the shutter 4 abut against the receiving pins 9 and the shutter 4 is thereby opened. The electrode terminals 3 of the card 1 are thereby brought into contact with electrode-contacting pieces (not shown) of the connector.
In this type of conventional memory card, the shutter 4 can be charged with static electricity such as frictional electricity caused by the opening-closing operation, or static electricity charged by human contact, and this static electricity causes, through the electrode terminals 3, malfunctions of the incorporated semiconductor module.